Does brand really matter when it comes to coating prep products? Generally I like to stick with one brand in most situations. However, in this case I am planning on applying Gyeon pure evo this weekend and I have about half a bottle of Blackfire paint prep left which will be more than enough. Part of me wants to buy Gyeon prep to keep it in the family but I`m not sure it really matters. Aren`t they all basically the same thing? Thoughts?